Most people don't know the basic scientific facts about happiness—about what brings it and what sustains it—and so they don't know how to use their money to acquire it. It is not surprising when wealthy people who know nothing about wine end up with cellars that aren't that much better stocked than their neighbors', and it should not be surprising when wealthy people who know nothing about happiness end up with lives that aren't that much happier than anyone else's. Money is an opportunity for happiness, but it is an opportunity that people routinely squander because the things they think will make them happy often don't.

From "If money doesn't make you happy, then you probably aren't spending it right" by Elizabeth W. Dunn, Daniel T. Gilbert, Timothy D. Wilson in the Journal of Consumer Psychology. (http://dunn.psych.ubc.ca/files/2011/04/Journal-of-consumer-psychology.pdf)